a=input("请输入第一个数字：")
b=input("请输入第二个数字：")
c=input("请输入第三个数字：")
if a.isdigit() and b.isdigit() and c.isdigit():
    a = int(a)
    b = int(b)
    c = int(c)
else:
    print("输入的内容有误！")
if a+b>c:
        print("ok")
elif a+c>b:
    print("ok")
elif b+c>a:
    print("ok")
else:
    print("no")